Cord equalizing mechanism for venetian blinds



Jan. 1, 1952 Y M. .1. s'roGRAN CORD EQUALIZING MECHANISM FOR VENTIAN BLINDS Filed Oct. 24. 1949 INVENTOR BY l Patented Jan. 1, 1952 j UNITED'STATES PATENT orslcs CORD EQUALIZING MECHANISM` FOR l VEN ETIAN BLINDS Max J. Stogran, Chicago, Ill. Application October 24, 1949, SerialNo. 123,257 e. Claims, (Cl. IBD-e176) My invention relates to the conventional type of.tilt mechanism for Venetian blinds, and more particularly to means incorporated` in such a mechanism for facilitating the equalizing o f the tilt cords.

One object of Athe present invention is. to provide a mechanism for the purpose mentioned which facilitates. `the `equalizine. acteu Without imposing wear on the tilt gearing. V

A further object,I is to design an equalizing mechanism whichis connedl to. the` tilt rail gear and extremely compact,`

Anotherobject is to construct an equalizing mechanism which is entirely automatic in operation and which utilizes the tension in the folding of the blind to restore. the `tilting facility to. the same after the tilt cords have been equalized.

An important obiectisto. employ a minimum number of. parts in the construction of the equalizer, so that it may add but slightly to the cost .of `the tilt gearing.

With the above objects in view, and any others which vmay suggest themselves from the de.- scription to follow, a better understanding of the invention may be had by reference to thc accompanying drawing, in which,-

l Fig. l isan elevation of a typical tilt gearing installation in a fragment of a Venetian blind;

Fig. 2 is an enlarged section on the line 2--2 ofFig; l;

Fig. 3 is a section on the line `3--3 of Fig; 2; Fig. 4 is a view similar to Fig. 2, showing the portion of the equalizing mechanism at one end of the tilt gearingtravel; and

Fig. l5 is a viewsimilar to Fig. 4 showing the portion of theequalizing mechanism at the other end of the tilt'gearing travel.

In accordance with vthe foregoing, specific reference to the drawing indicates the head rail of the Venetian blind at II), the tilt rail at II, the ladder tapes at I2, the slats at I3, the tilt cords at III 'and I5, and the guides for the same at IE. The tilt gearing is composed of a hanger 20, a spindle 2l journaled in the same and carrying a worm 22 and tiltcord pulley 23, and a gear-sector 24 in mesh with the worm 2,2 during the tilting operations. The worm gear is ex tended with a bracket 25 having a receptacle 26 for the spindle 21 of the tilt rail Il. Thus, when the slats I3 are level-as indicated in Fig.` l-the position of the gear-sector bracket 25. is. lowermost and also level, as seen in Fig. 2; aldown pullon the tilt cord i4 o r i3 serves to operate the worm `gearing and tilt the blindt accordingly. I

Repeated actuation of a tilt cord as mentioned induces a slight slippage of the. cord over` the` pulley. 23, so that in time the aiected cord. becomes considerably longer than its companion, and presents an unbalanced appearance. For this reason, one mechanism or another has been devised to permit thecords to. be threaded back freely over the pulley until they depend atsub.-` stantially equal length, this process being termed as the equalizing of the cords..

Inthe novel embodiment, the equalizing mech,-u anism resides in the assembly of the gear-sector 2li` with the hanger 2U. Thus, the latteris per'-` forated to receive.` `a rivet` 30. iormed" with a square head 3| on the rear sideof the hanger. On the frontal side the rivet is enlarged with a circular stud 32; and the latter is` enlarged with a circular plate 33.

The gear-sector 2li` is formedwith an elliptical opening 35., one of whose sides. is constrictecl to a pointed edge 36 at the middle, so that such` side forms a pair of adjoining pockets 3.1; and each of these is of a capacity to seat the stud 32, asshown in Figs. 4 and 5.` The edge of the plate 33 contains a substantially semi-circular notch or depression 4 9. at. the top., The gearsector 24 is stamped from the rear to project a pair of small circular studs 42- in forward direction. these being a short distance from the bracket and on cppositesides of the circular plate 33; `and the gear-sector has its nal teeth 4,4. continued as cams 4.5 which are inclined to meet the side edges of the bracket.

It is evident fromlig. 2` that when the `blind is openwith its slatsin the horizontal position shownthe gear-sector rests with the undivided,

. side of its opening 3.5 on the stud 3'2; and.. the

ends. of the opening are spaced equally from the stud by virtue of the studs 42, which. serve as bearings inrelation to the periphery ofhthe frontal plate 33..

When the gear-sector in the position. just described it is in full mesh with the worm22. Therefore, the rotation of the vlatter in either direction accomplishes the tilting of the blind accordingly. Ordinarily, the slats I3 close. in oyen-lapping sequence at the end of the tilting travelin either direction; and they are in substantially vertical position when closed. However, when it is desired to equalize the tilt cords I4: and I5, the. shorter one. of these should not only be pulled down to accomplish the closing otthe blind. as iust stated but pulled slightly'l lower. If this operation rotates the gear-sector in the counterclockwise direction from the position of Fig. 2, it is apparent from Fig. l that the eXtra downpull of the shorter cord has rotated the gear-sector to a point where its bracket 25 has passed the vertical position to the left as shown. This action brings the right hand stud 42 of Fig. V2 ,to a topmost position; and the weight of the blind plusthe clearance now af` forded bythe gear-sector opening 35 pull down on the gear-sector with the effect of seating the upper stud 42 in the notch 40 and lowering the gear-sector out of mesh withv the worm 22. Presumably, the downpull on the shorter cord may now be continued without affecting the blind, until both cords hang at equal length When the equalizing of thecords I4m and l5 has been accomplished as stated, it follows that the blind should be reopened to the level or tilted position, as desired. According to the postion of the parts in Fig. 4 this is not possible, as the gear-sector 2d and the' worm 22 are out of mesh. However, since the blind has been tilted beyond the end of its closing travel, and av wrapping pull imposed on its tapes I2, the tendency of these is to unwrap and urge the blind to rotate in the returning direction. This action is reflected in the urge upon the upper final tooth 44 and cam 45 to rotate in the clock- Wise direction. This urge has a lifting effect on the tooth 44, so that the latter trips the threads of the worm 22 as the same rotates on the downpull of the shorter cord section. However, if the other cord is pulled-aiter the cords have been equalized-and the worm rotated in the opposite direction, the nal gear-sector tooth 44 receives a positive urge in the clockwise direction by the foremost worm thread, this causing the gear-sector to lift the stud 4.2 out of the notch 4D. The stud now resumes its travel as a bearing to maintain the gear-sector centered on the stud 32 and therefore in mesh with the worm, so that the untilting or opening feed` of the blind follows.

It is now seen that one pocket 3l of the gearsector opening served as a clearance to permit the upper gear-sector stud 42 to fall into the notch 40. Fig. 5 shows the position of the parts when the other cord is 'the shorter one and is pulled as described to equalize the cords. The other stud 42 and pocket 31 now come into play, and the action is duplicated. l

It is now apparent that the novel equalizing mechanism isY actuated merely by the normal downpull of the shorter tilt cord to close the blind with final tension, this action automati-v cally releasing the cord pulley for free rotation to quickly equalize the cords. The equalizing mechanism is fully contained in the installation of the worm gearing, so that nothing projects therefrom to form an obstruction or complicate the tilt gearing. Further, the chambered construction of the gear-sector facilitates the quick and certain drop of the gear-sector to clear the worm for free rotation. Further, the studs 42 not only serve to cooperate with the notch 40 for the gear-sector dropping function, but serve at all other times as bearings to maintain the gear-sector in centered position. Finally, the parts entering the equalizing mechanism are few and quite simple, enabling the `mechanism to be produced at low cost.

While I have described the invention along speciilc lines, various minor changes or refinements may be made therein without departing from its principle, and I reserve the right t employ all such changes and refinements as may come within the scope and spirit of the appended claims.

I claim:

1. A tilt cord equalizing mechanism for Venetian blinds comprising a support, a spindle journaled in the latter and carrying a worm, apulley at one end of the spindle over which the tilt cords are trained. a. stud projecting forwardly from the support at a point below the worm, and a gear-sector normally in mesh with the Worm and adapted to be connected in supporting relation to one end of the blind tilt rail, said gear-sector having an internal opening for journaling the gear-sector on said stud for rotation in either direction to control said tilt rail accordingly, said opening being elongated in a direction'to create a clearance over the stud when the gear-sector has been rotated by the actuation of the shorter tilt cord to a point closing the blind with a slight subsequent tension, and said clearance permitting the gear-sector to drop a sufcient distance in such event to clear its teeth from the worm and permit the pulley to turn freely as said cord is drawn to a level even with its companion c-ord.

2. A tilt cord equalizing mechanism for Venetian blinds comprising a support, a spindle joui'- naled in the latter and carrying a worm. a pulley at one end or the spindle over which the tilt cords are trained, a stud projecting forwardly from the support at a point below the worm, and a gear-sector normally in mesh with the worm and adapted to be connected in supporting relation to one end of the blind tilt'rail, said gear-sector having an internal opening for centrally journaling the gear-sector on said stud for rotation in either direction to control said tilt rail accordingly, said opening beingY elon'` 3. The structure of claim 2, and means main- Y taining the gear-sector in centered position during the rotation period before said point.

4. The structure of claim 2, a frontal circular,

enlargement for said stud, and a pair of secondary studs carried by the gear-sector on opposite sidesk of said enlargement, said secondary studs serving as bearings for the gear-sector` around the periphery of the' enlargement during the rotation period of the gear-sector before said point to maintain the gear-sector in centered position during such rotation.

5. The structure of claim 2, a vfrontal circular enlargement for said stud, and a pair vof sec" ondary studs carried by the gear-sector on opposite sides of said enlargement, said secondary studs serving as bearings for the gear-sector around the periphery of the enlargement during the rotation period of the gear-sector before said point to maintain the gear-sector in centered position during suchrotation, and the positions of the secondary studs being such as to locate one or the other above the enlargement when the rotation of the gear-sector reaches vsaid point in the corresponding directionfand` the top of the enlargement having a. recess as a clearance to receive the stud over the enlargement in the event of said drop.

6. The structure of claim 1, the last gearsector tooth in said rotation terminating with a decline and tripping the threads of the Worm on the free rotation of the pulley and the tend ency of the gear-sector to reverse its rotation due to said tension, and such tension also urging the rise of the gear-sector and the meshing of said tooth into the Worm thread on the reverse rotation of the pulley to re-open the blind.

MAX J. STOGRAN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

